Pesticidal esters of 2,6-dinitro-4-alkyl phenols

ABSTRACT

Fungicidal compounds useful for the control of plant mildews are 4-alkyl-2,6-dinitrophenyl esters wherein the 4-alkyl group is selected from 1-ethyl-n-hexyl, 1-n-propyl-n-hexyl, 1-n-butyl-nhexyl, 1-n-pentyl-n-hexyl, 1-ethyl-n-pentyl, 1-n-propyl-n-pentyl, 1-n-butyl-n-pentyl and 1-n-propyl-n-butyl.

llnited States Patent [191 Pianka et a1.

[54] PESTIClDAL ESTERS 01F 2,6-DINITRO- 4-ALKYL PHENOLS [76] Inventors: Max Pianka, 67 Sandpit Lane, St. Albans, Hertfordshire; John Duncan Edwards, 60 Reginald Street, Luton, Bedfordshire, both of England [22] Filed: Aug. 27, 1970 [21] App1.No.: 67,583

Related US. Application Data [63] Continuation of Ser. No. 707,880, Feb. 23, 1968, abandoned, which is a continuation of Ser. No. 476,706, Aug. 2, 1965, abandoned [52] US. Cl. ...260/479 1R, 260/247.7 C, 260/29384, 260/404.5, 260/476 R, 260/479 S, 260/567.5, 260/612 D, 260/622 P, 260/624 E, 424/308, 424/317 [51] Int. Cl. ....C07c 69/24, C07c 69/52, C07c 69/78 [58] Field of Search ..260/476 R, 479 R {56] References Cited UNITED STATES PATENTS 2,526,660 10/1950 Hester et a1. ..260/479 2,861,915 11/1958 Cary ..260/479 2,862,022 11/1958 Cook et a1. ..260/479 OTHER PUBLICATIONS Clarke et al., Jour. Chem. Soc (London), 1962, pages 519521 Primary Examiner.lames A. Patten Attorney-Bacon & Thomas [57] ABSTRACT 13 Claims, No Drawings vided compounds of the general formula:-

oooit where either (A):

R represents a saturated or unsaturated aliphatic group which may be substituted with one or more of the following substitutents; halogen atoms, carboxy groups, alkoxy groups and alkoxycarbonyl groups or R represents a phenyl group or a halophenyl group, and R represents l-n-propyl-n-hexyl; l-n-butyl-n-hexyl; l-n-pentyl-n-hexyl; l-ethyln-pentyl; l-n-propyl-n-pentyl; l-n-butyl-n-pentyl or l-n-propyl-n-butyl; or (B): R represents an alkyl group, a halo-alkyl group, a phenyl group, a halo-phenyl group, or the group having the general formula:

where R represents hydrogen or an alkyl group and R and R are the same and both represent hydrogen or alkyl groups, or R represents hydrogen and R represents an alkoxy-carbonyl group, and R represents l-ethyl-n-hexyl.

R may thus for example, both under (A) and (B), be a branched or unbranched 0,13 unsaturated aliphatic group e.g., an aor B-alkyl vinyl group such as an amethyl vinyl group, a B,B-dimethyl vinyl group or a B- methoxy-carbonyl vinyl group. R may also in both cases be an alkyl group, for example one containing from one to ten carbon atoms such as methyl, ethyl, propyl, hexyl,octyl or decyl group,-or a haloalkyl group especially a chloroalkyl group containing from one to ten carbon atoms. Various methods have been proposed for the preparation of dinitro derivatives of hydrocarbon-substituted phenols but in many cases the products were mixtures of isomers. These mixtures included both position isomers and also isomers of the hydrocarbon side chain. Therefore, whichever method is adapted to prepare the alkyl phenols and their dinitro derivatives which are used to prepare the esters of the present invention, care should be taken to ensure that the desired compound is obtained.

The compounds according to the invention can be prepared from the corresponding 4-branched alkyl 2,6- dinitrophenols in any convenient manner.

A preferred method for preparing the compounds of the invention comprises reacting a phenol of the general formula:

(111) where R has any of the meanings given above, or a functional derivative of said phenol, with an acylating derivative of an acid of the general formula:

R.COOH where R has any of the meanings given above.

By a functional derivative of the phenol we mean such derivatives as alkali metal phenoxides which react with reagents such as acid halides to give the same product as does the parent phenol. The acylating derivative may be an anhydride or a halide such as a chloride or bromide. Where a phenol is used the reaction is preferably carried out in the presence of an acid binding agent, e.g., a tertiary base such as pyridine or dimethylaniline. The reaction is conveniently effected in the presence of an inert organic solvent such as diethyl ether, benzene or tetrahydrofuran.

In practice an alkali metal (e.g. sodium or potassium) phenoxide is conveniently used as a functional derivative of the phenol and a halide of the acid is reacted with the phenoxide in solution in inert organic solvent.

The phenoxide is preferably formed by reaction of an alkali metal hydroxide or a salt of an alkali metal and a weak acid with a solution of the 4-alkyl-2,6- dinitrophenol of formula (III) in an inert organic solvent, the latter also being a solvent for the phenoxide.

The 4alkyl-2,6-dinitrophenol of formula (III) is prepared by any convenient method, for example as described below. I

instead of using a performed alkali metal phenoxide the reaction may be effected by simultaneously reacting the carboxylic acid halide, 4-alkyl-2,6- dinitrophenol and alkali metal hydroxide or salt of an alkali metal and a weak acid in an inert organic solvent in which the alkali metal phenoxide is soluble.

Suitable solvents include ketones, preferably lower alkyl ketone's e.g., acetone, methyl ethyl ketone etc. The suitability of any solvent can be determined by preliminary experiment with a specimen of the alkali metal phenoxide. Sodium and potassium are preferred alkali metals.

The alkali metal compound used is preferably an alkali metal carbonate e.g., potassium carbonate or sodiurn carbonate.

The reactants are preferably used in substantially stoichiometrical quantities to avoid contamination of the resulting ester with impurities.

Reaction of the carboxylic acid halide with the phenoxide'or mixture of the phenol and alkali metal compound is conveniently effected at a temperature between 35 and lC., advantageously at the boiling point of the solvent used.

After the reaction is complete the reaction mixture is allowed to cool, precipitated alkali metal halide is filtered off and the solvent is removed under reduced pressure. Any contaminants in the resulting ester may be removed by washing e.g., with dilute alkali and water.

The esteriflcation reaction using an alkali metal phenoxide not only enables good yields of the desired ester to be obtained but also avoids the use of tertiary organic bases, e.g., pyridine. This preferred process is thus more economic.

The parent dinitro-alkyl phenols:-

NOz- N02 where R has any of the meanings given above may conveniently be prepared by dinitration of the corresponding alkylphenols. This dinitration may be carried out by an convenient method. However, a preferred method comprises adding the 4-alkyl phenol in solution in an inert organic solvent, particularly a hydrocarbon or a halogenated hydrocarbon solvent, to agitated aqueous nitric acid containing at least two equivalents of nitric acid; on completion of the addition raising the temperature of the reaction mixture to further the nitration; cooling the reaction mixture when the reaction is essentially complete and recovering the nitrated phenol.

The 4-alkylphenol may be dissolved in any desired inert organic solvent. However, it is convenient to use halogenated hydrocarbons, e.g., halogenated alkanes, in order to decrease the fire risk. Suitable solvents are thus ethylene dichloride and especially carbon tetrachloride.

In order to obtain the nitrated phenol it is necessary to use at least two equivalents of nitric acid and it is preferred to use from three to eight equivalents, preferably about 4 equivalents, in order to obtain optimum results. Moreover, it is preferred to employ aqueous nitric acid in which the concentration of nitric acid is initially from 6 N. to 10 N. The production of nitric acid of this concentration from commercial concentrated nitric acid and water involves the liberation of heat and it is desirable not to allow the temperature to exceed 35C. while the 4-alkylphenol solution is being added. After the addition is complete the temperature is then raised to further the nitration. Whilst temperature of 40-49C. may be employed, it has been found that a significant increase in purity may be obtained by completing the nitration reaction between 50C. and the boiling point of the reaction mixture. Indeed products of high purity are obtained by boiling the reaction mixture preferably under reflux.

When the nitration is to all practical purposes complete, the reaction mixture is cooled and the nitrated phenol recovered therefrom. This may be achieved by allowing the mixture to separate into two phases, discarding the aqueous phase and repeatedly washing the organic phase until the washings have pH circa 4. The solvent may then be removed under reduced pressure leaving the oily 4-alkyl-2,6- dinitrophenol.

Alkyl phenols analogous to those used to prepare the esters of the present invention have been prepared by reacting phenol with an alkylating agent e.g., an alkene or a mixture of an alkanol and a dehydrating agent. Using this process the alkylated product is a mixture of 2- and 4-alkyl phenols and further, a mixture of alkyl side chain isomers. To obtain substantially pure 4-alkyl phenol having the desired side chain structure it is necessary to fractionate the mixture e.g., by distillation before or after nitration.

One method of preparing the 4-alkyl phenols involves reacting a p-hydroxybenzoketone with an appropriate alkylmagnesium halide, to yield a tertiary carbinol, dehydration of the carbinol, followed by catalytic hydrogenation of the resultant olefin e.g., using palladium/charcoal in ethanol. Dehydration may occur spontaneously during heating or may be effected by the use of an acid catalyst e.g., potassium hydrogen sulphate, p-toluene sulphonic acid or sulphuric acid. Such a procedure ensures that the 4-alkyl group is branched in the precise manner desired. In some cases it may be advantageous to use the methyl ether of the benzoketone to improve solubility in the reaction solvent and/or to avoid side reactions, demethylation being carried out after reduction of the olefin.

The compounds according to the invention may be formulated for use in any desired way. Generally such formulations will include at least one such compound in association with a suitable carrier or diluent. If desired, there may be used in addition to such compound(s) one or more further pesticides e.g., other fungicides, acaricides or insecticides. Such carriers may be liquid or solid and designated to aid the application of the compound either by way of dispersing it where it is to be applied or to provide a formulation which can be made by the user into a dispersible preparation.

Liquid preparations thus include preparations of the compound in the form of solutions or emulsions which can be used on their own or be adapted to be made up with water or other diluents to form sprays etc.; in such cases the carrier is a solvent or emulsion base which is non-phytotoxic under the conditions of use. Generally such preparations will include a wetting, dispersing or emulsifying agent. Other liquid preparations include aerosols in which the compound is associated with a liquid carrier or propellant.

Solid preparations include dusts and wettable powders, granulates and pellets, and semi-solid preparations such as pastes. Such preparations may include inert solid or liquid diluents such as clays, which may themselves have wetting properties, and/or wetting, dispersing or emulsifying agents; binding and/or adhesive agents may also be included. Solid preparations also include thermal fumigating compositions wherein the compound is associated with a solid pyrotechnic component.

In order that the invention may be well understood the following examples are given by way of illustration only:

PREPARATION OF ALKYL PHENOLS The preparations of alkyl phenols was carried out as described above using an alkyl magnesium halide and a hydroxy'phenylketone or methoxyphenylketone followed by treatment with potassium hydrogen sulphate to give an olefin and reduction of the olefin by hydrogenation using palladium/charcoal in ethanol. Where it is necessary to use the anisole derivatives, methylation was carried out in a conventional manner using dimethylsulphate on the hydroxy ketone. The final demethylation was effected by heating with hydrobromic acid in acetic acid to give the phenol.

A typical preparation of an alkyl phenol is as follows:

PREPARATION OF 4-(1-n-propyl-n-butyl)phenol 1. Preparation of4-(1-n-propyl-n-butenyl)anisole n-Propyl bromide (42 g.) in sodium-dried ether (50 ml.) was added dropwise to magnesium (7.0g.) covered with sodium-dried ether (100 ml.) at such a rate as to maintain a vigorous reflux. After the addition the reflux was maintained for a further 1% hr., then p-methoxy-nbutyrophenone (45 g.) in sodium-dried ether (40 ml.) was added dropwise with stirring at a rate sufficient to maintain the reflux. After the addition the reaction mixture was heated under reflux for 3 hr., then cooled and poured onto crushed ice, and acidified with an excess of dilute sulphuric acid. The ether layer was separated, washed with water and distilled on a steambath at 20 mm. Concentrated sulphuric acid (9 drops) was added to the residue from the distillation, which was then heated at about 50C. overnight. Ether and dilute sodium hydroxide were added to the cooled mixture and the ether solution was separated, washed with water and dried over sodium sulphate. The. dried solution was filtered and distilled to give 4-(1-n-propyl'nbutenyl)anisole (41.9 g., 81 percent) b.p. 145150 C./17 mm., n 1.5239 (Found: C, 82.08; H, 9.87. C H O requires C, 82.35; H, 9.80%). 2. Preparation of 4-( 1-n-propyl-n-butyl)anisole 4-(1-n-Propyl-n-butenyl)anisole (41 g.) in absolute alcohol (25 ml.) was added to a suspension of a 10 percent palladium on charcoal catalyst (2 g.) in absolute alcohol (25 ml.) and the mixture hydrogenated at about atmospheric pressure. When the hydrogen uptake has ceased, the catalyst was filtered off and the filtrate distilled to give 4-(1-n-propyl-n-butyl)-anisole (37.1 g., 90 percent) b.p. 139-143C./15 mm. n,, l.4950 (Found: C, 81.42; H, 10.61 C H O requires C, 81.55; H,10.68 percent). 3. Demethylation of 4-(1-n-propyl-n-butyl)anisole to give 4-(1-n-propy1-n-butyl)-phenol 4-(l-n-Propyl-n-butyl)anisole (36 g.) was dissolved in a mixture of glacial acetic acid (250 ml.) and 47 percent aqueoushydrobromic acid (160.8 g.). The mixture was heated under reflux for 11 hr., cooled and extracted with light petroleum (b.p. 4060C., 2 portions, 100 ml., 50 ml.). The petroleum solution was washed with water, then with 2 portions (100 mls.) ofa mixture of 25 percent w/v aqueous NaOH (50 ml.) and methanol (50 ml.). The combined alkaline extracts were washed with light petroleum (b.p. 40-60C., 100 ml.), then acidified with concentrated hydrochloric acid. The liberated phenol was extracted with petroleum (b.p. 40-60C., 2 portions, 100 ml.,50ml) and the petroleum solution was washed with water, dried (Na SO and distilled to give 4-(1-n-propyl-n-butyl)- phenol (31,35 g., 93.4 percent) b.p. 156-160C.

(mainly 158 l59C.)/19 mm., solidifying to needless.

mp. 61-64C. (softening at 57C). (Found: C, 81.17; H, 10.35. C H O requires C, 81.25; H, 10.42 percent).

A further typical example of the preparation of an alkyl phenol is now given with reference to the preparation of pure 2,6dinitro-4-( 1-ethyl-n-hexyl)phenol from a crude nitration product of technical caprylphenol.

a. Isolation of the cyclohexylamine salts of 2,6-dinitro- 4-( l-ethyl-n-hexyl)phenol and 2,4-dinitro-6-(1-methyl heptyl)phenol To the crude nitration product of technical caprylphenol (2 kg) prepared by reacting capryl alcohol and phenol in the presence of sulphuric acid which is in fact a mixture of 2-and 4-octylphenols) dissolved in petrol, (b.p. 60 (4 liters) and cooled in a mixture of ice and water, cyclohexylamine (480 g) was added below 40 over 25 min. while stirring. The mixture was stirred until it reached room temperature, then thesolid salt was filtered off, washed with petrol (b.p. 60 80C), stirred with more petrol, filtered again, and washed again with petrol. The solid was then dissolved at reflux in ethyl acetate (1 liter), and petrol (b.p. 60 80) (200 cc.) was added under reflux until the solution became turbid. It was then allowed to cool slowly.

The first crop of crystals that precipitated out was then filtered off and washed with petrol. 1t weighted 724 g. and melted at 145 147. A second crop was obtained by concentrating the filtrate. This solid was of an orange color and melted at 123 126C.

The first crop was then recrystallized again from a mixture of isopropanol and di-isopropyl ether. The cyclohexylamine salt of 2,4-dinitro-6-( l-methyl-n-heptyl)pheno1 was obtained as bright yellow prisms, m.p. l51151.5.

The second crop, consisting of an orange colored solid, mp. 123-126 obtained as mentioned above by concentrating the filtrate, was further purified by recrystallizing from a mixture ofisopropanol (twice the weight of solid) and di-isopropyl ether (4 times the weight of solid). The cyclohexylamine salt of 2,6- dinitro-4-(1-ethyl-n-hexyl)phenol was obtained as bright orange-colored needles, mp. 163-164.5. b. 2,6-Dinitro-4-(1-ethyl-n-hexyl)pheno1 from cyclohexylamine salt The cyclohexylamine salt of 2,6-dinitro-4-( l-ethyl-nhexyl)phenol was suspended in petrol (b.p. 60 80C) 2 liters), stirred and refluxed. A solution of an equal weight of concentrated hydrochloric acid (37% w/w) in twice the weight of water was then added. The mixture was refluxed for 3 hours with stirring, cooled, the petrol layer separated, washed with water, dried over anhydrous sodium sulphate and the solvent distilled off first at atmospheric pressure, then at and 0.5 mm for 2 hours. 2,6-Dinitro-4-(1-ethyl-n-hexyl)phenol was obtained as a yellow oil, n 1.5465 (Found: N, 9.8. C,,H N O requires N, 9.5%).

The following salts of 2,6-dinitro-4-( l-ethyl-n-hexyl) phenol were prepared the Recrystallization Salt solvents M.p. Morpholine a mixture of 124-125 (orange plates) ligroin and benzene, then di-isopropyl ether Piperidine ligroin, then 112-113 (orange plates) petrol (b.p. 60- 80) Table I give the characteristics of the resulting 4- alkyl phenols.

C Preparation of Esters The esters were all prepared from the corresponding 2,6-dinitro-4-alkyl phenols using the general method TABLE] given below for 2,6-dinitro-4-(1-ethyl-n-hexyl)phenyl Analysis 5 acrylate (1.e. the compound of Example 15. M1111 -P- R EmPm- Result PREPARATION OF 2 6-Dinitro-4-(1-ethyl-nsubstltut1ve calent of index Formula C H C H hexyl)phenyl acrylate h {111111101 11,, 2.6-D1n1tro-4-(1-ethy1-n-hexyl)pheno1 (4.5 g.) was 10 dissolved in acetone (10 ml.) and potassium carbonate Solid (1.1 g.) was added to the solution. The mixture was pyl-n- 159 m.p. C H O 81.17 10.35 81.25 10.42 then refluxed for one-half hr. The resulting solution butyl 19 mm6l-64C o o lmhylm 1.5105 CmHmo 81.33 1015 M25 1042 was cooled to to C. and acrylyl chlor1de (1.4 g.) 1n -pentyl 155 (17) solut1on 1n acetone ml.) added dropw1se over a I {3 rd [5 period of 7 minutes. The mixture was allowed to stand pm 3 CHHHO 8134 1097 8155 [Q68 for one-half hr. and then refluxed for 2 hours. Th e mixpentyl l 1.8 mm. 36d-37C ture was then cooled and the prec1p1tated sol1d f11tered l-n-buty 180 soli mmmp. CHHHO H06 1093 82 10.9 off. The solvent was removed from the filtrate under 55C reduced pressure. The resldue was d1ssolved 1n ml. l-ethyl-n 153- a l -h0Xyl 154 1.5070 c,.11,,o 79.16 10.25 81.55 10.68 20 Petroleum 60 80 C) the resultmg lo ug) t1on shaken w1th 2N sodium carbonate (25 ml.) unt1l -p there was no longer a red layer present at the solvent Kim lg g 8 interface. The petroleum-ether solution was separated l-n-butyl 186- and washed w1th a 5 percent solut1on of sodium li g g CIBHHO 8205 82-06 25 chloride (25 ml.) The petroleum-ether solution was 131,5 dried over sodium sulphate, filtered and the solvent y 432 9 CHI-[2110 10-77 82-24 11-29 removed under reduced pressure (2 mm.), 2,6-Dinitrohcxyl mmun 4-(1-ethyl-n-hexy1)phenyl acrylate was obtained as a pale brown oil (3.6 g.). The physical data of the crotonyl esters of the Exampreparatllonhof i gg f l g lireparatlon of ples are given in Table 111. in Table 111 the groups R exy 1 lmtrop eno and R refer to the substitutents in the general formula To 4-(1-n-propyl-n-hexyl)-phenol (19.2 g.) 1n

. OCO-CH=CH'CI{3 ethylene d1chlor1de (34.1 ml.) a m1xture of conc. n1tr1c acid (69-72% HNO 22.5 ml.) and water (22.5 ml.) N02 "N02 was added. The mixture was heated under reflux for 1% hr. The ethylene dichloride layer was separated off, washed with saturated aqueous sodium sulphate solution, dried over anhydrous sodium sulphate and filtered. The ethylene dichloride was removed from the 40 R R4 W dried solution. The residue was dissolved in light 3 and s being norma alkyl groups The esters were Petroleum -P- 40 i 125 cyclohexylamme oils ranging from pale yellow to red brown in color. (15 ml.) was added and the m1xture refr1gerated. The BL m orange colored crystals that separated were filtered off TA E (24 g.), m.p. 162-164. After recrystallization from 33 E Refrac- E I Analysis percent aqueous isopropanol the salt had m.p. 165-16 4 mp'nca 6 (20.7 g.). It was dlSSOlVCd 111 methanol and the solu- No. indegr Formula Found required tion acidified with conc. hydrochloric acid. The mix- 1, 1 I N(%) N(%) ture was diluted with water and the brown oil that precipitated was extracted with light petroleum, hp. a 1238 9 :22:28:

I 19 s -80. The petroleum extract was washed w1th water, 3 C.H,, C511,. 1521! 20 111 z 11 y i 4 H C H 1.519% 6.9 dr1ed over anhydrous sodium sulphate, filtered, the 5 2 5236 Z T74 8m petroleum was removed from the filtrate. 4-(1-n- 6 L527; CWHHNQOG 731 Propyl-n-hexyl)-2,6-dinitrophenol was obtained as an 7 CJHI 1 9 1-5210 m ze z o -32 oil (14.9 g.). 55 The physical data of three esters of 4(1-n-propyl-n- .Table 11 shows the physical characteristics ofthis and pentyl)-2,6-dinitrophenol which were prepared are other dinitroalkyl phenols also prepared via their given below in Table IV (with reference to the group R cyclohexylamine salts. in Formula 1).

TABLE 11 M.p.of eyelohexyl- Refraetlve Found, ltr-qulrerl, 4-a1kylsubst1tuentol amine salt, index of Emplrlcal N N the2,6-dlnltrophenol degrees phenol formula percent percent lurpropyl-n-butyl 197-11111 11 15528 (liiH sN m 11.8 11.11 l-et yl-n-pentyl 171172 11p1.5526 (11 111 1920 10.2 11.11 1-n-propy1-n-penty1 1711.5-181 11 1 16482 CHNmHQOs 11. 25 11. 46 l-n-butyl-n-peutyl 184-185 11 15435 0111111110. 114 11.03 l-ethyl-n-hexyl.-. 164-166 11D7'JL5464 CuHzoNzOs 11.88 11.46 l-n-propyl-n-hoxyl 165-166 11 1.5424 CuHgzNzOs 8.95 11. 03 l-n-butyl-n-hexyl. 180-182 1115 115382 C15II24N205 8.115 8. 64 I-n-pentyl-n-hexyl 183-184 n 1.5345 C H NzOs 8.22 8.30

' Recrystalllsed from aqueous isopropanol.

TABLE IV Refrac- Ex. tive Empirical Analysis No.

R lndex(n,,") Formula Found Required CH 60 C H N O 8.9 8.3

C(CH 1.5242 C H N O 7.3 7.7 =CH,

CH 1.5098 CmHgqNzOg 7.6 7.65 M

The physical data of various esters of 4-( l-ethyl-n-hexyl)-2,6-dinitrophenol which were prepared are given below in Table V again with reference to the group R in Formula I. The esters of both Table IV above and Table V below were oils ranging in color from pale yellow to red brown at about C except where otherwise stated.

TABLEV Analyses Refractive Empirical Ex.

R index(n,,") Formula found required No. N(%) CH 51.5-53.5"C C H MO 8.5 8.3

yellow 2 crystals 1 C,H 1.5096 C,,H,,N,O I3

I C H 1.5110 C,,.H,,N,0., 7.6 14

CH(CH 1.5073(n,,) C H MO 7.7 7.6 15

CH=CH 1.5268 C H MO 8.0 8.0 16

C(CH;)=.CH, m.p.

44-45C C,,,H, N,0 7.5 7.7

cream 7 crystals 1 CH=C(C1-l;,), 1.5297 C H MO 7.4 7.4 18 19 CH=CHCO Me-1.5258 n u a n CH,C1 1.5309

(nn c,.H,.ClN,o, 8.0 7.5 20

CHClCl-l, 1.5202 C H ClN,O, 7.0 7.2 2| CH,CH,C1 1.5243 C H CIMO ch82 22 CH, 1.5585 C,,H, N,0. 7.0 7.0

p-Cl.C.,H,- 1.5604 C H ClN Ofi 6.33 Cl:8.08 Cl:8.l7

mildewicidal activity. The results obtained in tests and the methods oftesting are shown below.

The products were in all cases formulated using 25 g. of the active compound, 4 g. of calcium dodecyl benzene sulphonate, 4 g. of ethoxylated nonyl phenol and heavy naphtha to give ml.

APPLE MILDEW ERADICANT TEST.

Applerootstocks were kept in a cool greenhouse and allowed to become infected with apple mildew originating from infected rootstocks kept in the same house. Before application of the toxicant dilution, the amount of mildew present on each rootstock was assessed by grading each leaf according to the percentage of the leaf area covered by apparently active mildew infection, the scale used being as follows:

Grade 0 no mildew present Grade 1 0 3% of leaf area infected by mildew Grade 2 4 7% of leaf area infected by mildew Grade 3 8 17% ofleaf area infected by mildew Grade 4 18-41% of leaf area infected by mildew Grade 5 42-100% ofleaf area infected by mildew The mildew on the leaves was assessed up to a certain height of the apple rootstocks. A tag was placed above the uppermost leaf assessed to ensure that the same leaves would be assessed after treatment.

After assessment, the plants were divided up into four groups, to be considered as blocks in the experimental design, each group being as homogeneous as possible in respect of mildew infection of the plants. Within the groups a single plant fro each treatment was used, making a total of four replicate plants per treatment. Spraying was by high volume hand sprayer, sufficient spray being applied to ensure thorough coverage. The sprays were prepared by diluting the formulation to give 20 p.p.m. of the test compound in the spray. To ensure good wetting, sodium dioctyl sulphosuccinate 'was included at 100 p.p.m. After spraying, the plants were arranged in the cool greenhouse to form four randomized blocks.

Four days later the mildew infection was again assessed; only the area of active mildew was taken into account.

The mean grade per leaf for the four replicates was calculated and these grades were used for the statistical analysis.

Differences between means grades before treatment were not significantly great at the 5 percent level, so percentage control was calculated by comparing the mean grades per leaf (of the four replicates combined) for each treatment with the mean grade per leaf for the untreated rootstocks. 1

BARLEY MILDEW ERADICANT TEST Pots containing 10 barley seedlings were kept in six groups, each group being considered as a block in the experimental design and containing one pot for each treatment. The seedlings were infected by blowing spores from infected plants over them, after all leaves except the oldest had been removed from each plant.

After the infection had developed sufficiently, the amount of mildew present was assessed by grading the leaves according to the scale given in the apple mildew test.

The plants were then treated by dipping for 15 seconds in a dilution containing the test compound at 20 p.p.m. and sodium dioctyl sulphosuccinate at 300 P-P- After treatment the plants were kept in a cool greenhouse for 4 days, after which they were assessed using the same grades as previously. Active mildew only was assessed.

A mean grade per leaf was calculated for each replicate, and these grades were used for a statistical analysis. Since the difference between the mean grades before treatment were not significantly different at the 5 percent level, percentage control was calculated by comparing the mean grade per leaf (of the six replicates combined) with the mean grade per leaf of the untreated seedlings.

CUCUMBER MILDEW ERADICANT TEST This followed the test described for apple mildew except that young cucumber plants with two leaves were used. The grading of mildew on the cucumber plants before infection was as follows:

Grade no mildew present Grade 1 0.5% of leaf area infected by mildew Grade 2 1% ofleaf area infected by mildew Grade 3 2% ofleaf area infected by mildew Grade 4 4% ofleaf area infected by mildew Grade 5 8% ofleaf area infected by mildew Grade 6 16% of leaf area infected by mildew Grade 7 32% ofleaf area infected by mildew Grade 8 a 64% ofleaf area infected by mildew No wetting agent was added to the toxicant spray.

The following results were obtained:

We claim: 1. A compound of the formula OCOR wherein R is selected from the group consisting of CH=CH CH=CHCH --C(CH )=CH CH=C(CH CH=CHCO CH CH -CH CH CH CH CH CH(CH CH Cl, CHClCH -CH CH Cl,

Cl and R is selected from the group consisting of lethyl-n-hexyl, l-n-propyl-n-hexyl, l-n-butyl-n-hexyl, ln-pentyl-n-hexyl, l-ethyl-n-pentyl, l-n-propyl-n-pentyl, l-n-butyl-n-pentyl and l-n-propyl-n-butyl, R being other than l-cthyl-n-hexyl when R is CH=CHCH 2. A compound as claimed in claim 1 in which R represents methyl or vinyl.

3. The compound of claim 1 which is 2,6-dinitr0-4-(l -n-propyl-n-butyl) phenyl crotonate.

4. The compound of claim 1 which is 2,6-dinitro-4-(l -n-propyl-n-hexyl) phenyl crotonate.

5. The compound of claim 1 which is 2,6-dinitro-4-(1 -n-butyl-n-hexyl) phenyl crotonate.

6. The compound of claim 1 which is 2,6-dinitro-4-(l -n-pentyl-n-hexyl) phenyl crotonate.

7. The compound of claim 1 which is 2,6-dinitro-4-(l -ethyl-n-pentyl) phenyl crotonate.

8.'The compound of claim 1 which is 2,6-dinitro-4-(l -n-propyl-n-pentyl) phenyl crotonate.

9. The compound of claim 1 which is 2,6-dinitro-4-(1 -n-butyl-n-pentyl) phenyl crotonate.

10. The compound of claim 1 which is 2,6-dinitro-4- (l-ethyl-n-hexyl) phenyl acetate.

11. The compound of claim 1 which is 2,6-dinitro-4- (l-ethyl-n-hexyl) phenyl acrylate.

12. The compound of claim 1 which is 2,6-dinitro-4- (l-ethyl-n-hexyl) phenyl a-methyl acrylate.

13. The compound of claim 1 which is 2,6-dinitro-4- (l-ethyl-n-hexyl) phenyl a-chloropropionate. 

1. A compound of the formula
 2. A compound as claimed in claim 1 in which R represents methyl or vinyl.
 3. The compound of claim 1 which is 2,6-dinitro-4-(1-n-propyl-n-butyl) phenyl crotonate.
 4. The compound of claim 1 which is 2,6-dinitro-4-(1-n-propyl-n-hexyl) phenyl crotonate.
 5. The compound of claim 1 which is 2,6-dinitro-4-(1-n-butyl-n-hexyl) phenyl crotonate.
 6. The compound of claim 1 which is 2,6-dinitro-4-(1-n-pentyl-n-hexyl) phenyl crotonate.
 7. The compound of claim 1 which is 2,6-dinitro-4-(1-ethyl-n-pentyl) phenyl crotonate.
 8. The compound of claim 1 which is 2,6-dinitro-4-(1-n-propyl-n-pentyl) phenyl crotonate.
 9. The compound of claim 1 which is 2,6-dinitro-4-(1-n-butyl-n-pentyl) phenyl crotonate.
 10. The compound of claim 1 which is 2,6-dinitro-4-(1-ethyl-n-hexyl) phenyl acetate.
 11. The compound of claim 1 which is 2,6-dinitro-4-(1-ethyl-n-hexyl) phenyl acrylate.
 12. The compound of claim 1 which is 2,6-dinitro-4-(1-ethyl-n-hexyl) phenyl Alpha -methyl acrylate. 